What exactly constitutes a “mobile device”? It’s a debate that’s been going on for quite some time and revolves around whether the term includes smartphones, tablets and other things like e-readers, game controllers and wearable tech, or whether it just covers mobile phones.

When the Securities and Exchange Commission asked Google last year to disclose the amount of revenue it generates from mobile devices, the debate about what constitutes a mobile device was pushed to the forefront.

Google’s reply was that it doesn’t make sense to try and break out mobile revenue in earnings because mobile platforms, and their definition, change “from period to period.”

In their response, Google also suggested that, in the next few years, it’s quite possible that they’ll be serving ads on a wide variety of new devices including glasses, car dashboards, refrigerators, watches and even thermostats.

“Because users will increasingly view ads and make purchase decisions on and across multiple devices, our view of revenue is similarly device-agnostic,” it stated.

When Google first introduced their Enhanced Campaigns, what they were trying to do is convince marketers that serving ads on smartphones and tablets was a good idea. At the time many were reluctant to do so because they didn’t yet have the capability to manage the complex accounts necessary to do so and mobile optimized screens weren’t yet available.

Now Google’s laying out their vision of what a streamlined ad buying process across multiple screens looks like, even though it doesn’t exactly exist just yet.

Google is still waiting for their CPC on mobile devices to catch up to desktop as far as revenue generation is concerned. They believe that, in time, desktop pricing will be surpassed by mobile and thus conversions, as well as higher ad rates, will follow.

That hasn’t happened yet, however. Why? Larger desktop screens are still driving sales better than mobile. During their latest earnings call Nikesh Arora, Google’s SVP and chief business officer, had this to say; “That journey is just beginning for advertisers in the mobile site. They’re just beginning to understand what it takes for the end user to come transact on their website.”

Most marketers “are indifferent to whether or not Google or Facebook ads run on desktop or mobile environments,” argued senior analyst Brian Weiser of Pivotal Research Group, whose company included a research note to the SEC.

There is definitely a difference in performance between mobile and desktop and, knowing that, Google allows marketers to manage their bids and track their results by specific devices. If Google’s correct, the distinction among devices may soon fade as performance becomes more consistent across multiple screens.

That being said, a seamless digital media world is still a long way off, making analysts wonder why Google won’t provide marketers and investors more information about how their business is being affected by the mobile shift, something that stands in stark contrast to one of their biggest competitors, Facebook.